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Calibration of the test stand MZGS-200 and the monitoring of fatigue experiments using LabVIEW
Klus, Jakub ; Doložílek, Miroslav (referee) ; Slámečka, Karel (advisor)
This bachelor work concerns with the calibration method of the fatigue test stand MZGS-200, monitoring of fatigue experiments and analyzes signal retrieved from tenzometers. Work includes theoretical derivation of the equation describing force acting on the specimen. Two programs in LabVIEW environment were developed for calibration and measurements. The functionality of those programs was veried during fatigue experiments on specimens made of nickel-based superalloy Inconel 713LC. The measurements of mechanical loading by means of tenzometres were compared with optical measurements using noncontact laser sensor optoNCDT.
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Identification of fatigue damage Al alloy treated with SLM technology using acoustic emission method
Zemanová, Lucie ; Mazůrek, Ivan (referee) ; Mazal, Pavel (advisor)
The aim of the diploma thesis is to study fatigue properties of EN AW-2618A aluminium alloy produced by selective laser melting (SLM). S-N diagrams of reference alloy and SLM material depending on manufacturing conditions were constructed. Reference alloy had the same chemical composition as the SLM material, but it was made by traditional technology (by extruding). While testing, acoustic emission (AE) and resonant frequency of loading was monitored. Fractographic analyses of fracture surfaces were performed. It was found, that SLM material has significantly worse fatigue performance. Fatigue properties are strongly dependent on SLM process parameters settings and precise observance of procedure. The most significant differences in cyclic degradation were found in the length of the stages of fatigue. The more homogeneous the material is, the longer the nucleation stage compared to the total lifetime is. The main source of AE in case of the reference material is plastic deformation on the tip of the crack. For SLM testing, stronger acoustic activity was recorded, because brittle fracture of the material between discontinuities, which is stronger AE source, is more frequent.
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Fatigue Properties of Ultra-fine Grain Copper Produced by ECAP Method
Navrátilová, Lucie ; Němec, Karel (referee) ; Pantělejev, Libor (advisor)
This diploma thesis describes properties of ultra-fine grain Cu prepared via ECAP procedure. The influence of fatigue loading with positive mean stress on S-N curve (i.e. fatigue life), cyclic plastic behaviour and grain size was investigated. It was found that tensile mean stress leads to shorter lifetime in comparison with fatigue loading with zero mean stress. During main part of the lifetime, significant hardening of UFG Cu was observed. There is no distinct effect on microstructural orientation and stability.
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Wing fatigue safe life investigation of single-engine multipurpose aircraft
Hubáček, Jan ; Juračka, Jaroslav (referee) ; Chybík, Ladislav (advisor)
Práce se zabývá stanovením bezpečné únavové životnosti křídla. Letadlo, které bylo podrobeno analýze, je vzpěrový hornoplošník celokovové konstrukce. Letadlo je certifikováno na základě předpisu FAR 23 Amendment 23-46. Výpočet bezpečné únavové životnosti musí být proveden v souladu s požadavky předpisu FAR 23 a jeho poradními oběžníky.\\ Teoretická část práce je věnována hlavně přehledu literatury a představení projektu, kde byla stručně shrnuta jeho historie vzniku. Část přehledu projektu také pojednává o podstatě požadavku na posouzení bezpečné únavové životnosti zadavatelem. V další části byl rovněž proveden rozbor literatury týkající se únavy. Jednalo se zejména o rozbor předpisu FAR 23, jeho poradních oběžníků a obecně literatury vztahující se k únavě jak v letectví, tak v obecném strojírenství.\\ Druhá část diplomové práce byla zaměřena zejména na výpočetní analýzu a vývoj specializovaného software. Výpočetní část obsahovala zejména přípravu vstupů, včetně obálek zatížení, stanovení typického letu, výpočet zatížení křídla a napjatostní analýza ve vybraných řezech křídla. Z výstupů prvotní analýzy se následně provedl výpočet poškození a životnosti pro daný typový let.
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Fatigue behavior of high strength steels (S460, S690 and S960) after corrosion
Benešová, Anna ; Květoň, Josef (referee) ; Seitl, Stanislav (advisor)
The subject of this diploma thesis is the issue of the interaction of fatigue stress and corrosion on high-strength steel. Specifically, S 460, S 690, S 960 were selected. This work presents the results of fatigue experiments on test samples that were degraded by four types of corrosion, mainly in artificial atmospheres. Subsequently, fatigue models were calculated from these data, which describe the fatigue behavior of these steels and were compared with each other. At the end, photographs of fracture surfaces of broken samples of these steels were taken, which were analyzed and their fatigue behavior was discussed with their help together with the created fatigue models.
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Analysis of the use of Code_Aster in solving the limit state of fatigue strength
Busta, Michal ; Kovář, Jaroslav (referee) ; Vosynek, Petr (advisor)
This bachelor’s thesis deals with the analysis of the use of Code_Aster in the calculations of the limit state of fatigue strength. The first part is the research in fatigue analysis using the solver Code_Aster and in the second part the know-how of Code_Aster usage is used to solve three tasks of the limit state of fatigue strength. Acquired results are compared with analytical solutions and with the student licence of the numerical software Ansys Workbench 19.2. In conclusion, all the results are analysed.
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